求助：这个程序，从a链表中删除与b链表学号相同的元素。为什么运行时出错呢？

#include <iostream>
using namespace std;
struct student
{
    int num;
    char name[10];
    student *next;
}a[5]={{101,"feng"},{102,"wang"},{103,"li"},{104,"qiu"},{105,"tong"}},
b[3]={{101,"lian"},{102,"luo"},{103,"zhou"}};
int main()
{
    int i;
    student *head1,*head2,*p0,*p1,*p2;
    head1=a;
    head2=b;
    for(p1=head1,i=1;i<5;i++)
    {
        p1->next=a+i;
        p1=p1->next;
    }
    p1->next=NULL;
    for(p2=head2,i=1;i<3;i++)
    {p2->next=b+i;
    p2=p2->next;
    }
    p2->next=NULL;

    p0=p1=head1;
    while(p1)
    {
        p2=head2;
        while(p2!=NULL&&p1->num!=p2->num)
        p2=p2->next;
        if(p1->num==p2->num)
        if(p1==head1)head1=head1->next;
        else p0->next=p1->next;
        p0=p1;
        p1=p1->next;
    }      //如果注释了这一段，运行还是正常的...
    p1=head1;
    while(p1)
    {cout<<p1->num<<' '<<p1->name<<endl;
    p1=p1->next;
    }
/*
    p2=head2;
    while(p2)
    {cout<<p2->num<<' '<<p2->name<<endl;
    p2=p2->next;
    }*/


    return 0;
}
这个程序哪里出错呢？？？？多谢各位大侠！